scholarly journals Observation of Intermode Coupling in the 3μm IR Multiple Photon Excitation of Propylene

1983 ◽  
Vol 1 (5) ◽  
pp. 177-183 ◽  
Author(s):  
R. L. Woodin ◽  
C. F. Meyer
Keyword(s):  
Energy Deposition ◽  
Excited Molecule ◽  
Vibrational Modes ◽  
Vibrational States ◽  
Vibrationally Excited ◽  
Laser Chemistry ◽  
Methyl Group ◽  
Photon Excitation ◽  
Deuterium Substitution

The mechanism of IR multiple photon excitation through the dense manifold of vibrational states, usually called the quasicontinuum, of a vibrationally excited molecule is one of the unresolved issues in the field of laser chemistry. The effects of deuterium substitution on propylene IR multiple photon excitation are used to identify the vibrational modes leading to efficient excitation. Optoacoustic energy deposition data show that for propylene, 3 μm multiple photon excitation occurs most efficiently at the methyl group, and furthermore that efficient methyl group excitation requires the CH group on the adjacent carbon. Thus 3 μm multiple photon excitation of propylene, while involving energy deposition directly into several spatially discrete intramolecular groups, is found to be enhanced by specific intramolecular couplings. Implications of this result for mechanisms of IR multiple photon excitation are discussed.

scholarly journals Picosecond Anti-Stokes Raman Excitation Profiles as a Method for Investigating Vibrationally Excited Transients

1999 ◽  
Vol 19 (1-4) ◽  
pp. 335-341 ◽  
Author(s):  
Hiromi Okamoto ◽  
Takakazu Nakabayashi ◽  
Mitsuo Tasumi
Keyword(s):  
Vibrational Energy ◽  
Vibrational Modes ◽  
Vibrational States ◽  
Vibrationally Excited ◽  
Quantum Numbers ◽  
Trans Stilbene ◽  
Raman Process ◽  
Vibrationally Hot Molecules ◽  
Raman Excitation Profiles ◽  
Anti Stokes

A method for estimating vibrational quantum numbers of vibrationally excited transients in solution is proposed. In this method, we calculate anti-Stokes Raman excitation profiles (REPs) which are characteristic of the initial vibrational states involved in the Raman process, and compare them with observed anti-Stokes intensities. We have applied this method to vibrationally hot molecules of canthaxanthin in the So state and those of trans-stilbene in the S1 state. For canthaxanthin, it has been found that the vibrationally excited transients are for the most part on the ν=1 level of the C═C stretching mode, and that excess vibrational energy is statistically distributed among all intramolecular vibrational modes. As for S1 stilbene, vibrational transients are shown to be mostly on the ν=1 level for two vibrational modes examined, while the excess vibrational energy is probably localised on the olefinic C═C stretching mode.

scholarly journals Stimulated-Emission-Pumping Laser-Induced-Fluorescence Spectroscopy of Phenol and Anisole

1994 ◽  
Vol 14 (1-3) ◽  
pp. 103-117 ◽  
Author(s):  
Masao Takayanagi ◽  
Ichiro Hanazaki
Keyword(s):  
Vibrational Relaxation ◽  
Dynamical Behavior ◽  
Low Frequency ◽  
Laser Induced Fluorescence ◽  
Stimulated Emission ◽  
Torsional Motion ◽  
Vibrational States ◽  
Vibrationally Excited ◽  
Supersonic Expansion ◽  
Methyl Group

The SEP–LIF (stimulated emission pumping-laser induced fluorescence) technique was applied to the investigation of dynamical behavior of vibrationally excited phenol and anisole produced in the supersonic expansion. In the SEP–LIF scheme, a molecule excited to a specific vibrational state by SEP is detected by measuring the LIF excitation spectrum with an appropriate delay to probe the vibrational relaxation. Four vibrational states, 6a1, 16a2, 121 and 11, of phenol, and six vibrational states, 18b1, 18b2, 6a1, 121, 16a2 and 11, of anisole were investigated. For both of phenol and anisole, it is found that the relaxation of the vibrational states below 1,000 cm-1 in the ground electronic state is so slow under the collisionless condition that only the transitions from the vibrational states initially prepared by SEP are observed as the SEP-induced bands in the SEP–LIF spectra. The low frequency torsional motion of methyl group in anisole does not accelerate IVR (intramolecular vibrational redistribution) much in this energy region.

scholarly journals Microwave Spectra of Furazan. III. Rotation Spectra of Vibrationally Excited States

1990 ◽  
Vol 45 (9-10) ◽  
pp. 1117-1130
Author(s):  
Otto L. Stiefvater
Keyword(s):  
Excited States ◽  
Heterocyclic Compound ◽  
Microwave Spectroscopy ◽  
Vibrational Modes ◽  
Vibrationally Excited ◽  
Rotational Constants ◽  
Rotational Spectra ◽  
Microwave Spectra

Abstract The pure rotational spectra of molecules in 21 vibrationally excited states of the heterocyclic compound furazan (C2H2N2O) have been detected and studied by DRM microwave spectroscopy. Rotational parameters are reported for the 12 fundamental levels below 1500 cm-1 , and the contri-butions from 10 vibrational modes to the effective rotational constants and to the inertia defect of furazan are calculated.

scholarly journals Microwave Spectrum and Nuclear Quadrupole Interaction of 3-Bromothiophene in Excited Vibrational States

1983 ◽  
Vol 38 (12) ◽  
pp. 1309-1319 ◽  
Author(s):  
Yoshiaki Sasada
Keyword(s):  
Excited States ◽  
Nuclear Quadrupole Interaction ◽  
Coupling Constants ◽  
Vibrational Modes ◽  
Centrifugal Distortion ◽  
Vibrational States ◽  
Rotational Spectra ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole ◽  
Centrifugal Distortion Constants

Abstract The rotational spectra of 3-bromothiophene in the excited states of two vibrational modes were observed and the rotational constants, the centrifugal distortion constants, and the nuclear quadrupole coupling constants were determined. The wave numbers of the two vibrational modes were evaluated to be 210 cm-1 and 320 cm-1 by measuring relative intensities of the ground and excited vibrational transitions. Variations in the inertia defect for each of the vibrational modes are compared with the results of the approximate calculation.

Nuclear Reaction Spectroscopy of Vibrational Modes of Solids

1986 ◽  
Vol 82 ◽  
Author(s):  
M. Zinke-Allmang ◽  
S. Kalbitzer ◽  
M. Weiser
Keyword(s):  
Elastic Scattering ◽  
Nuclear Reaction ◽  
Vibrational Spectroscopy ◽  
Process Parameters ◽  
Target Atom ◽  
Vibrational Modes ◽  
Doppler Broadening ◽  
Vibrational States ◽  
Specific Process ◽  
Theoretical Predictions

ABSTRACTThe effects of target-atom vibrations on nuclear reaction kinetics have been examined. In particular, Doppler broadening of resonance-type and elastic- scattering reactions has been considered in detail. Depending on the specific process parameters, the resulting energy widths can be many orders of magnitude larger than the energies of the vibrational states of the target solid. Comparison of experimental results on a hydrogen-bearing thin target with the theoretical predictions shows excellent agreement. We will show the importance of this effect in hydrogen profiling measurements and point out the feasibility of vibrational spectroscopy on hydrogen in solids.

scholarly journals Model of daytime emissions of electronically-vibrationally excited products of O<sub>3</sub> and O<sub>2</sub> photolysis: application to ozone retrieval

2006 ◽  
Vol 24 (11) ◽  
pp. 2823-2839 ◽  
Author(s):  
V. A. Yankovsky ◽  
R. O. Manuilova
Keyword(s):  
Atomic Oxygen ◽  
Energy Exchange ◽  
Electronic States ◽  
Vibrational States ◽  
Vibrationally Excited ◽  
Proposed Model ◽  
Vibrational Levels ◽  
Electronically Excited ◽  
Basic Facts ◽  
Kinetics Of

Abstract. The traditional kinetics of electronically excited products of O3 and O2 photolysis is supplemented with the processes of the energy transfer between electronically-vibrationally excited levels O2(a1Δg, v) and O2(b1Σ+g, v), excited atomic oxygen O(1D), and the O2 molecules in the ground electronic state O2(X3Σg−, v). In contrast to the previous models of kinetics of O2(a1Δg) and O2 (b1Σ+g), our model takes into consideration the following basic facts: first, photolysis of O3 and O2 and the processes of energy exchange between the metastable products of photolysis involve generation of oxygen molecules on highly excited vibrational levels in all considered electronic states – b1Σ+g, a1Δg and X3Σg−; second, the absorption of solar radiation not only leads to populating the electronic states on vibrational levels with vibrational quantum number v equal to 0 – O2(b1Σ+g, v=0) (at 762 nm) and O2(a1Δg, v=0) (at 1.27 µm), but also leads to populating the excited electronic–vibrational states O2(b1Σ+g, v=1) and O2(b1Σ+g, v=2) (at 689 nm and 629 nm). The proposed model allows one to calculate not only the vertical profiles of the O2(a1Δg, v=0) and O2(b1Σ

Determination of a High Potential Barrier Hindering Internal Rotation in 2-Methylcyclopentanone and α-Methyl-γ-Butyrolactone by Microwave Fourier Transform Spectroscopy

1992 ◽  
Vol 47 (6) ◽  
pp. 761-764 ◽  
Author(s):  
J. L. Alonso ◽  
N. Heineking ◽  
H. Dreizler ◽  
N. Heineking ◽  
H. Dreizler
Keyword(s):  
Fourier Transform ◽  
Internal Rotation ◽  
Excited States ◽  
Fourier Transform Spectroscopy ◽  
Vibrationally Excited ◽  
Methyl Group ◽  
Internal Rotation Barrier ◽  
High Potential Barrier ◽  
Method Analysis

AbstractThe microwave spectra of α-methyl-γ-butyrolactone and 2-methylcyclopentanone have been reinvestigated using microwave Fourier transform spectroscopy. A-E splittings due to internal rotation of the methyl group have been observed in the ground and several vibrationally excited states for both molecules. From an internal-axis-method analysis of these splittings, values of the methyl group internal rotation barrier of 2.61 kcal mol-1 for α-methyl-γ-butyrolactone and 2.41 kcal mol-1 for 2-methylcyclopentanone have been obtained.

IR spectrum of highly vibrationally excited osmium tetraoxide in the region of strong nonlinear interaction of vibrational modes

1990 ◽  
Vol 94 (4) ◽  
pp. 1294-1297 ◽  
Author(s):  
O. V. Boyarkin ◽  
S. I. Ionov ◽  
A. A. Stuchebrukhov ◽  
V. N. Bagratashvili ◽  
M. S. Dzhidzhoev
Keyword(s):  
Ir Spectrum ◽  
Nonlinear Interaction ◽  
Vibrational Modes ◽  
Vibrationally Excited ◽  
Osmium Tetraoxide
Sign in / Sign up

Export Citation Format

Share Document